I worked at an auto parts store during the early 70s while going to college. Due to the proximity of farm ground to the store, many of our customers were farm laborers who worked the fields during the spring and summer, then went home to Mexico during the winter. It was common practice for them to cash their checks as soon as they got them, and take any leftover cash home when they went. Although silver had already been virtually phased out, quite often these guys would bring in silver dollars and other coins that they had taken home years ago, and brought back for their return trip. They'd spend them on auto parts in the store, and at the end of the day the manager would let me buy the silver out of the register.
I have 37 silver dollars of various years, and about another $50 or so of silver dimes, quarters, half dollars, and a bunch of buffalo nickels. None are rare collectibles, though.